An energy absorption apparatus or spring is known to be used in various applications and between two masses. For example, a spring is commonly used and forms an integral part of a railroad car side bearing assembly. During movement of the railcar, the spring of the railcar side bearing assembly acts an energy absorption apparatus which serves to control or restrict “hunting” movements and limit “rolling” movements of the railcar about a longitudinal centerline.
Alternatively, an energy absorption apparatus or spring is frequently used as a part of a railcar buffer assembly, railcar drawbar assembly or railcar draft gear assembly. Each of these railcar devices typically include one or more springs for absorbing, dissipating, and returning energy between adjacent ends of two railcars. As will be appreciated, an increased ability to control impacts between adjacent railcars tends to increase performance characteristics of the railcar components as well as add protection to the lading carried and shipped within the railcar.
A significantly large amount of energy and excessive resultant dynamic impacts can develop in many devices which utilize a spring for damping such forces. Accordingly, the materials forming the spring must have great strength or they will likely fail under substantial end loads placed thereon, and energy impacts imparted thereto during daily operation of such devices. As will be appreciated, adverse temperature conditions only exacerbate spring problems.
In the railroad industry, it is known to equip a side bearing assembly with a cylindrically shaped column of rubber-like material. The column-like shape of the spring maximizes the volume of the spring thus allowing the spring to absorb, dissipate and return energy axially imparted thereto. As will be appreciated by those skilled in the art, and during axial compression thereof, the cylindrically shaped column of rubber-like material forming the spring tends to radially bulge outwardly. In fact, during maximum axial compression, the spring develops a very significant bulge about the longitudinal center of the spring.
Radial bulging of the spring can and often does cause serious problems. That is, lateral and longitudinal size constraints of a walled housing wherein the spring is arranged limits the size and, thus, performance characteristics of the spring. As will be appreciated, significant radial bulging of the spring can cause the spring to engage and rub excessively on the surrounding walled housing. When the spring rubs on the housing, the material from which the spring is formed is degraded and, thus, often causes premature failure of the mechanism with which the spring is operably associated.
Thus, there is a continuing need and desire for a simple but strong, reliable and yet inexpensive spring which offers the necessary force/deflection curve for the particular application and yet is designed to limit the radial bulging of the spring during operation thereof